I'm not entirely positive how to recreate this other than going to sites that use a lot of AJAX and letting it fill up a buffer, with multiple AJAX heavy pages open in tabs [I usually have 3-4]. This happens to me about 2-3 times a day [in Safari 3.1.x as well] but never with the same set of sites open or the same order.
I've attached the stack trace so it will hopefully generate a better understanding of what's happening.
Created attachment 21627 [details]
Bug report for JS Crash
Please try uninstalling Inquisitor and seeing if that helps. The attached crash report doesn't seem like something related to a bug that could persist from Safari 3.1.1 to recent nightlies (although it's hard to say for sure, of course).
For now, I'm resolving as INVALID because of Inquisitor (and it's certainly not a common experience to have frequent crashes with Safari 3.1.1!). Please feel free to re-open if you continue seeing the problem after uninstalling SIMBL and Inquisitor.
Created attachment 21732 [details]
Non-Inquisitor installed Crashed
This crash report came after SIMBL and Inquisitor were uninstalled.
Reopening because the same crash appeared after uninstalling inquisitor/SIMBL.
I'm going to close this bug since (1) it is reporting an issue in a 3 year old Safari, and likely since been fixed, (2) the code has changed so much in the JS engine that the attached stack trace is going to be no help in tracking down an issue.
If you can still reproduce this crash, then please reopen, and attach an updated stack trace!